Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Property, Plant and Equipment - Components of Property, Plant and Equipment (Detail)

v3.7.0.1
Property, Plant and Equipment - Components of Property, Plant and Equipment (Detail) - USD ($)
$ in Millions
 12 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Mar. 31, 2015
Property, Plant and Equipment [Line Items]      
Cost, Beginning balance $ 1,542.0 $ 1,533.5  
Additions 113.2 78.6  
Disposals (57.4) (68.0)  
Exchange differences (3.7) (2.1)  
Cost, Ending balance 1,646.3 1,542.0 $ 1,533.5
Other (6.1)    
Adjustment 58.3    
Accumulated depreciation, Beginning balance (675.0) (653.4)  
Charge for the year (80.3) (76.3) (70.2)
Disposals 42.4 51.6  
Exchange differences 2.3 3.1  
Accumulated depreciation, Ending balance (767.3) (675.0) (653.4)
Other 1.6    
Adjustment (58.3)    
Net book amount 879.0 867.0  
Land [Member]      
Property, Plant and Equipment [Line Items]      
Cost, Beginning balance 70.1 70.2  
Additions 1.3    
Exchange differences (0.4) (0.1)  
Cost, Ending balance 69.5 70.1 70.2
Transfers 1.9    
Adjustment (3.4)    
Net book amount 69.5 70.1  
Buildings [Member]      
Property, Plant and Equipment [Line Items]      
Cost, Beginning balance 266.0 239.8  
Additions 2.3 27.0  
Disposals (1.4) (0.7)  
Exchange differences (0.8) (0.1)  
Cost, Ending balance 344.5 266.0 239.8
Transfers 23.1    
Other (12.5)    
Adjustment 67.8    
Accumulated depreciation, Beginning balance (98.2) (88.2)  
Charge for the year (10.2) (10.7)  
Disposals 1.3 0.5  
Exchange differences 0.3 0.2  
Accumulated depreciation, Ending balance (128.0) (98.2) (88.2)
Other 1.6    
Adjustment (22.8)    
Net book amount 216.5 167.8  
Machinery and Equipment [Member]      
Property, Plant and Equipment [Line Items]      
Cost, Beginning balance 1,062.4 974.6  
Additions 27.8 155.5  
Disposals (55.5) (65.8)  
Exchange differences (2.4) (1.9)  
Cost, Ending balance 1,175.7 1,062.4 974.6
Transfers 112.3    
Adjustment 31.1    
Accumulated depreciation, Beginning balance (576.8) (565.2)  
Charge for the year (70.1) (65.6)  
Disposals 41.1 51.1  
Exchange differences 2.0 2.9  
Accumulated depreciation, Ending balance (639.3) (576.8) (565.2)
Adjustment (35.5)    
Net book amount 536.4 485.6  
Construction in Progress [Member]      
Property, Plant and Equipment [Line Items]      
Cost, Beginning balance 143.5 248.9  
Additions 81.8 (103.9)  
Disposals (0.5) (1.5)  
Exchange differences (0.1)    
Cost, Ending balance 56.6 143.5 $ 248.9
Transfers (137.3)    
Other 6.4    
Adjustment (37.2)    
Net book amount $ 56.6 $ 143.5